This invention relates to a dispensing valve of the automatically-sealing or self-closing type mounted on the cooperating spout of a container for liquids or other substances.
It relates more specifically to the type of dispensing valve known in the prior art as a toggle valve, a good example of which is illustrated in the U.S. Pat. No. No. 4,444,340 to Bond et al. which shows it applied to a flexible bag. This valve has an outer wall which engages the spout and which has an outlet beyond the outer end of the spout. It also has a resiliently flexible wall structure which normally engages the spout to seal the outlet. However, a toggle lever is connected to the flexible wall structure so that a portion therof can be flexed away from the spout to open a passage to the dispensing outlet. With this type of valve non-evident tampering with the contents of the container which carries it can occur readily merely by pressing on the toggle to open the outlet and inserting or passing some contaminant through the opened outlet into the container. There is a need for a sealing means which will readily indicate any tampering of the valve to open the outlet in an attempt to add anything to the container contents through the outlet.